Performance monitoring and notification in a threshold sensitive storage management system

ABSTRACT

A method for monitoring according to a hint when allocating a storage volume. When a threshold value violation has occurred, judgement is performed from which use purpose the threshold value derives. The management computer for managing a computer system includes a unit for creating a storage volume according to a hint, a unit for deciding a threshold value for managing the storage volume according to the use purpose of the storage volume, a unit for acquiring a performance value from the storage apparatus, and a unit for comparing the acquired performance value to the threshold value and notifying a warning including a message based on the hint when a threshold value violation is detected.

BACKGROUND OF THE INVENTION

The present invention relates to a computer system management programfor managing a computer system including a computer and a storageapparatus, a recording medium, a computer system, a management apparatusand a storage apparatus thereof, and in particular to a technique forsetting a monitoring unit of a computer system by utilizing a hint usedin operation of allocating a storage area in a storage apparatus andupon notifying a warning in the monitoring unit, creating an additionalmessage of warning according to the hint and notifying it together withthe warning.

Among monitoring systems monitoring a computer system, there is oneutilizing a threshold value. The monitoring system acquires fromrespective apparatuses constituting a computer system, a numerical value(mainly, a performance value) indicating the state of the apparatusesand compares the value with a predetermined threshold value. If theformer exceeds (is greater than or smaller than) the threshold value, awarning is generated.

When using this kind of monitoring system, there is a problem that it isdifficult to select an appropriate threshold value. To cope with this,JP-A-2002-215230 discloses a method for easily setting an optimalthreshold value. This method is as follows. Firstly, a user(administrator of the computer system) specifies the target number ofthreshold value violations of the numerical value indicating the stateof the apparatuses to be managed for the monitoring system. Next, themonitoring system automatically adjusts the threshold value so that thenumber of threshold value violations of the numerical value indicatingthe state of the apparatuses to be managed is identical to the specifiedtarget threshold value violation number.

Nowadays, together with monitoring of the computer system, a large-scalestorage apparatus such as a disk array apparatus, especially a storageregion provided by a large-scale storage apparatus has become animportant item to be managed. As a main component of the computersystem, a storage area network is now widely used. This storage areanetwork uses a fibre channel (FC) for connecting the computer to thestorage apparatus in a network type format, thereby flexibly connectinga computer to a storage apparatus. Thus, for example, it is possible toperform data backup without using LAN (local area network), therebyenabling a new application.

Moreover, as a network connecting a computer to a storage apparatus,some techniques using IP (Internet Protocol) network attract attentionand are widely spread. Under such a condition, an enterpriseorganization SNIA (Storage Networking Industry Association) has beenorganized by enterprises concerning storage network.

SNIA is promoting spread of the storage network through the activity offormulation of the standard specification of the storage network andperipheral technique. For example, SNIA suggests a standardspecification for operation of allocating a storage area in a computerin the computer system including the storage apparatus. Thisspecification is applied to management software managing a computersystem. Moreover, this specification is based on CIM (Common InformationModel) defined by DMTF (Distributed Management Task Force).

In the operation of this standard storage area allocation, a parameterindicating the storage area feature is defined. When allocating astorage area, an administrator creates this parameter for the userpurpose of the storage area and inputs it to the management software,thereby creating a desired storage area. This parameter is called“hint”.

A portion associated with the hints is extracted below from the documentdefining the specification (Device 27_StorageServices. mof (lines 662 to721) [online], Nov. 12, 2002, Distributed Management Task Force,[searched on Jan. 18, 2003], Internet

<URL:http://www.dmtf.org/standards/cim_schema_v27.php>.================================================== //StorageSettingWithHints //================================================== [Experimental,Version (“2.7.1”), Description ( “This subclass of Storage Settingallows a client to specify” “’hint’s for optimization of the volumeperformance. The effect” “of these hints is implementation dependent.”)]class CIM_StorageSettingWithHints: CIM_StorageSetting{ [MinValue (0),MaxValue (10), Description ( “This hint is an indication from a clientof the importance” “placed on data availability. Values are 0 = Don'tCare to” “10 = Very Important.”)] uint 16 DataAvailabilityHint;[MinValue (0), MaxValue (10), Description ( “This hint is an indicationfrom a client of the randomness” “of accesses. Values are 0 = EntirelySequential to” “10 = Entirely Random.”)] uint 16 AccessRandomnessHint;[MinValue (0), MaxValue (10), Description ( “This hint is an indicationfrom a client of the direction” “of accesses. Values are 0 = EntirelyRead to” “10 = Entirely Write.”)] uint 16 AccessDirectionHint;[Description ( “This hint is an indication from a client of the optimal”“access sizes. Several sizes can be specified.”), Units (“MegaBytes”)]uint 16 AccessSizeHint #; [MinValue (0), MaxValue (10), Description (“This hint is an indication from a client how important” “access latencyis. Values are 0 = Don't Care to” “10 = Very important.”)] uint 16AccessLatencyHint; [MinValue (0), MaxValue (10), Description ( “Thishint is an indication from a client of bandwidth” “prioritization.Values are 0 = Don't Care to” “10 = Very important.”)] uint 16AccessBandwidthWeight; [MinValue (0), MaxValue (10), Description ( “Thishint is an indication of the importance the client” “places on the costof storage. Values are 0 = Don't Care to” “10 = Very important. AStorage Volume provider might choose” “to place data on low cost or highcost drives based on” “this parameter.”)] uint 16 StorageCostHint;[MinValue (0), MaxValue (10), Description ( “This hint is an indicationof the importance placed on” “storage efficiency by the client. Valuesare 0 = Don't Care” “to 10 = Very important. A Storage Volume providermight choose” “different RAID levels based on this hint.”)] uint 16StorageEfficiencyHint; };

The management software mounting CIM should handle the hints in mountingoperation of the storage volume allocation.

SUMMARY OF THE INVENTION

In management of a computer system including a storage apparatus, it isnecessary to configure monitoring based on a hint when a storage volumeis allocated. When applying JP-A-2002-215230 to this, it is difficult toset a target number of the threshold value violations from the hint.Conventionally, there has not been a method for monitoring according tothe storage volume hint.

Moreover, in the conventional monitoring system, it has been impossibleto judge from which hint a threshold value violation derives when onehas occurred and a system administrator has had difficulty to study acountermeasure to be taken for the threshold value violation.

It is therefore an object of the present invention to provide atechnique for managing a computer system including a storage apparatus,the technique monitoring the computer system by using a hint in thestorage volume allocation.

According to another aspect of the present invention, there is provideda technique for simultaneously notifying a warning explanation includingthe cause of the warning in the monitoring of the computer system.

In order to achieve the object of the present invention, a managementcomputer managing the computer system includes: a unit for creating astorage volume according to a parameter indicating a characteristic ofthe storage volume; a unit for deciding a threshold value for managingthe storage volume according to the parameter; a unit for acquiring aperformance value from the storage apparatus; and a unit for comparingthe acquired performance value to the threshold value and detecting athreshold value violation.

Moreover, the management computer for managing the computer systemincludes a unit for notifying a warning when the threshold valueviolation is detected.

Moreover, the management computer for managing the computer systemincludes a unit for adding a message to the warning according to theparameter.

Moreover, the message suggests use of a unit for improving theperformance of the storage apparatus. The management computer formanaging the computer system has the warning notification unit whichcontains a unit for including in the message a suggestion of use of theunit for improving the performance of the storage apparatus.

According to the present invention, it is possible to monitor thecomputer system appropriately for the use purpose according to theparameter derived from the use purpose of the storage region whenallocating a storage volume, i.e., according to the hint.

Moreover, from the monitoring system of the computer system, it ispossible to rapidly grasp from which hint the notified warningapparatuses when a threshold value violation has occurred. Accordingly,a system administrator can rapidly examine a countermeasure to be takenfor the threshold value violation.

The other features of the present invention will be made clear in thedetailed description below and the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an outline of an embodiment.

FIG. 2 shows configuration of a computer system according to a firstembodiment.

FIG. 3 explains storage volume management information in the firstembodiment.

FIG. 4 shows a redundant group and a logical volume.

FIG. 5 explains allocation management information in the firstembodiment.

FIG. 6 explains flow of logical volume allocation processing in thefirst embodiment.

FIG. 7 explains threshold value information in the first embodiment.

FIG. 8 explains a table for deciding a threshold value in the firstembodiment.

FIG. 9 explains performance information in the first embodiment.

FIG. 10 explains flow of performance information acquisition processingin the first embodiment.

FIG. 11 explains flow of warning notification processing in the firstembodiment.

FIG. 12 shows the entire computer system according to a secondembodiment.

DESCRIPTION OF THE EMBODIMENTS

Description will now be directed to embodiments of the present inventionwith reference to the attached drawings.

Firstly, referring to FIG. 1, explanation will be given on the outlineof the embodiment of the present invention. FIG. 1 is a diagram forexplaining three processes: storage volume allocation by anadministrator, monitoring setting by the management system, andmonitoring and warning notification by the management system.

Explanation will be given on each component constituting FIG. 1. Anadministrator 3000 is a person who manages the computer system 3100. Themanagement system 3200 is a part of the computer system 3100 havingmanagement unit for managing the computer system 3100. The managementsystem 3200 as the management unit, includes at least a storageallocation section 110, a threshold composing section 120, a performanceinformation acquisition section 130, and a warning notification section140. The computer system 3100 includes at least a storage apparatus3300. A storage volume 3310 is a storage volume created in the storageapparatus 3300 by the storage allocation section 110.

Hereinafter, explanation will be given on each of the aforementionedthree processes. In the process of storage volume allocation operation,the administrator instructs the storage allocation section 110 toperform allocation of a storage volume (arrow 3601). Here, the parameter(hint 3400) indicating the characteristic of the storage volume isnotified to the storage allocation section 110. The storage allocationsection 110 creates a preferable storage volume 3310 in the storageapparatus 330 according to the hint (arrow 3602). The hint 3400 isstored in the management system 3200 (hint 3401). As will be detailedlater, the hint 3401 is referenced by the threshold composing section120 and the warning notification section 140.

In the monitoring setting process by the management system, thethreshold composing section 120 sets a threshold value for theperformance information of the storage volume 3310 according to the hint3401. Here, the relationship between the hint 3401 and the thresholdvalue is also recorded.

In the monitoring and warning notification process by the managementsystem, firstly, the performance information acquisition section 130acquires performance information from the storage apparatus 3300 (arrow3603). Next, the warning notification section 140 compares the acquiredperformance information to the aforementioned threshold value. If theperformance information exceeds (greater than or smaller than) thethreshold value, warning is issued to the administrator 3000 (arrow3604). Here, the warning notification section 140 analyzes how thethreshold value is related to the hint and notifies the threshold valueviolation to the administrator as well as notifies a message based onthe hint.

It should be noted that in FIG. 1, the storage allocation section 110,the threshold composing section 120, the performance informationacquisition section 130, and the warning notification section 140 aredepicted outside the storage apparatus but a part or all of them may bearranged inside the storage apparatus 3300.

[First Embodiment]

Hereinafter, explanation will be given on the first embodiment of thepresent invention. FIG. 2 shows configuration of the computer systemaccording to the first embodiment of the present invention. As shown inFIG. 2, the first embodiment of the present invention includes amanagement computer 100, a storage apparatus 200, an LAN 300, computers400(a) and 400(b), and an FC switch 500.

The management computer 100 is an ordinary computer including a CPU 101,a memory 102, a network interface 103, a display device, a hard disk, akeyboard, a mouse, and the like and capable of operating softwareincluding various operating systems. In this embodiment, the managementcomputer 100 is a personal computer. It may also be a computer forworkstation and a server or a general-purpose computer. It should benoted that in FIG. 2, other than the CPU 101, the memory 102, and thenetwork interface 103 are omitted.

The management computer 100 includes a storage allocation section 110, athreshold composing section 120, performance information acquisitionsection 130, and a warning notification section 140. The components 110to 140 are programs executable by the management computer 100. That is,the components 110 to 140 are stored in the memory 102 or the hard diskof the management computer 100 and interpreted/executed by the CPU 101of the management computer 100. Thus, the management computer 100functions as a computer system management apparatus for managing thecomputer system including the storage apparatus 200.

Moreover, the management computer has allocation management information150, performance information 160, and threshold value information 170.Each of the information 150 to 170 is stored in the memory 102 of themanagement computer 100 or the hard disk and information read, addition,correction, and deletion are performed by the program executed on themanagement computer 100.

The storage apparatus 200 includes a CPU 201, a memory 202, a networkinterface 203, a controller 210 a storage volume management section 220,storage volume management information 230, a storage volume allocationsection 240, a performance value notification section 250, logicalvolumes 260 to 264, and an FC interface 270. Each of the logical volumes260 to 264 can be accessed from the computer as a read/write-enabledstorage region (equivalent to a logical unit in SCSI). The read/writeaccess to the logical volumes by the computer is realized by datacommunication via the FC interface 270. This data communication uses theSCSI (Small Computer System Interface) protocol.

It should be noted the computers 400(a) and 400(b) can communicate withthe storage apparatus 200 by using their FC interfaces 410(a) and410(b), respectively. By this, the computers 400(a) and 400(b) requestthe storage apparatus 200 to read/write to/from the logical volumes 260to 264. The storage apparatus 200 receives the read/write request fromthe computers 400(a) and 400(b) via the FC interface 270. The computers400(a) and 400(b) and the interfaces of the storage apparatus 200 areconnected via an FC switch 500.

The controller 210 processes the read/write request to the logicalvolumes 260 to 264 from the computer 400(a) and 400(b). According to therequest, the controller 210 performs data transfer to the computer400(a) and 400(b) or data storage into the logical volumes. Moreover,the controller 210 drives the storage volume management section 220, thestorage volume allocation section 240, and the performance notificationsection 250. In this embodiment, the controller 210 includes a CPU 201and a memory 202 and has capability to interpret/execute a program. Thesections 220, 240, and 250 are programs stored in the memory 202 andexecuted by the controller 210. It should be noted that the presentinvention can also be implemented by using a storage apparatus in whichthe functions equivalent to the sections 220, 240, and 250 are mountedby the dedicated hardware.

The storage storage apparatus 200 uses a plurality of hard disks incombination to obtain the so-called RAID function improving thereliability and performance. The logical volumes 260 to 264 use the RAIDfunction to divide the storage volumes of the hard disks of the storageapparatus 200 and concatenate them. In FIG. 2, the hard disks of thestorage apparatus 200 are not depicted.

The storage volume management section 220 is a section for managing suchlogical volumes. The storage volume management information 230 isinformation for managing the allocation state of the logical volumes.The storage volume management information 230 is stored in the memoryregion of the controller 210. The storage volume management information230 is used by the storage volume management section 220, the storagevolume allocation section 240, the controller 210, and the performancenotification section 250. The storage volume management information willbe detailed later.

The storage volume allocation section 240 provides a function toconstitute a new logical volume in the storage apparatus 200. Anexternal computer performs data communication with the storage apparatus200 via LAN 300, thereby instructing creation of a new logical volume.The controller 210 receives such an instruction and drives the storagevolume allocation section 240 to create the instructed logical volume.

The performance notification section 250 notifies the performance valuesof the logical volume of the storage apparatus 200 and the FC interfacevia the LAN 300 to the external computer. In this embodiment, thestorage apparatus 200 outputs at least (1) average I/O size of writerequests to the logical volume (in kilobyte), (2) average data transferrate of the write requests to the logical volume per second (inkilobyte), (3) average processing wait time of write requests to thelogical volume (in second), (4) average number of write requests to thelogical volume per second, (5) average I/O size of read requests to thelogical volume (in kilobyte), (6) average data transfer amount of readrequests to the logical volume per second (in kilobyte), (7) averageprocessing wait time of the read requests to the logical volume (insecond), and (8) performance value of the average number of readrequests to the logical volume.

Here, the average processing wait time in (3) and (6) is an averagevalue of time from the moment when the controller receives theread/write processing to the moment when transmission of all the datarequested is complete. This time includes wait time in data transfer tothe hard disk or from the hard disk.

The computers 400(a) and 400(b) are ordinary computers including a CPU4001(a) and 401(b), memories 402(a) and 402(b), network interfaces403(a) and 403(b), display devices, hard disk devices, keyboards,mouses, and the like and can operate software including an operatingsystem. In FIG. 2, the components other than the CPU, memories andnetwork interfaces are omitted.

In this embodiment, the computers 400(a) and 400(b) are used to operatesoftware relating to enterprise activities such as a database server anda Web server. The main purpose of use of the logical volume of thestorage apparatus 200 by the computers 400(a) and 400(b) is to storedata required by these software.

In this embodiment, the read/write request by the computers 400(a) and400(b) is communicated only via the FC interface 410(a) and 410(b). Thisembodiment of the present invention can also be realized by using LAN300 for the read/write request. On the contrary, this embodiment of thepresent invention can also be realized by using the FC interface for themanagement data communication of the storage apparatus 200 (logicalvolume creation, performance value output). It should be noted that inthis embodiment, the two computers 400(a) and 400(b) are used for jobpurpose. However, the number of computers is not limited to thisaccording to the present invention.

Next, explanation will be given on the logical volume and hard disk ofthe storage apparatus 200 and a redundant group. Here, the redundantgroup is defined as a set of a plurality of hard disks includingredundant data for data protection in a storage sub-system having theRAID function such as the storage apparatus 200. According to thestorage sub-system, the redundant group is called a RAID group, paritygroup, or the like.

As a combination of hard disks in the redundant group, there is known aconcept of the RAID level. The redundant group of the storage apparatus200 is at either RAID level 1 or RAID level 5. Moreover, the redundantgroup of the storage apparatus 200 consists of four hard disks.

Terms concerning the redundant group are defined below:

Hard disk number: Numbers 0 to 3 assigned to hard disks belonging to theredundant group.

Hard disk ID: Numbers, different from the hard disk number, startingfrom 0 uniquely assigned to the hard disks in the entire storageapparatus 200.

Logical block address (LBA): Numbers starting from 0 assigned to eachlogical block consisting of 512 bytes of the storage region of the harddisk.

Striping unit: Hard disks belonging to a redundant group divided into apredetermined continuous number of logical blocks. Striping unit numberis assigned to the striping unit in the order of LBA.

Stripe: Striping units of each hard disk belonging to a redundant groupand having identical striping unit number. The striping units areconcatenated in the ascending order of the hard disk number and assumedto be a continuous single region.

Redundant group number: Unique identification number in the storageapparatus assigned to the redundant group.

In the case of the redundant group composed as the RAID level 5, on oneof the striping units belonging to the stripe, parity data calculatedfrom the other three stripes is recorded. In this embodiment, the paritydata is arranged by employing the method called left-symmetric paritydistribution.

In the case of the redundant group composed as the RAID level 1, on thestriping units (of the even numbers of the striping unit) having thehard disk number 0 and 2, the same information is recorded while on thestriping unit (of the odd numbers of the striping unit) having the harddisk number 1 and 3 the same information is recorded. Moreover, thestriping units of the even numbers and the striping units of the oddnumbers are handled alternately as a continuous storage region. Thelogical volumes 260 to 264 are composed of some continuous stripes. Suchconfiguration of the logical volume is recorded in the storage regionmanagement information 230 in the storage apparatus 200.

Explanation will be given on the storage region management information230 with reference to FIG. 3. The storage region management information230 includes two types of information: redundant group managementinformation 230 and the logical volume management information 232. Theredundant group management information 231 uses a table format such as arelation database as the data format. Each line of it has one-to-onecorrespondence with the redundant group arranged in the storageapparatus 200 and has a field for storing information constituting theredundant group. It should be noted that the fields in the table arecalled a first field, a second field, . . . starting from the leftmostof the figure.

The first field of the redundant group management information 231 storesthe redundant group number where the logical volume corresponding to theline is composed. Moreover, the second field stores the RAID level ofthe redundant group specified by the redundant group number stored inthe first field.

Moreover, the third field stores a hard disk ID of the first hard diskamong the hard disks constituting the redundant group specified by theredundant group number stored in the first group.

In this embodiment, the redundant group of the storage apparatus 200 iscomposed of four hard disks of continuous hard disk ID. Accordingly, theredundant group management information 231 does not contain a field forstoring the number of hard disks constituting the redundant group.

The logical volume management information 232 also uses a table formatas the data format like the redundant group management information 231.Each line of it has one-to-one correspondence with the logical volumearranged in the storage apparatus 200 and has a field for storingconfiguration information on the logical volume.

The first field of the logical volume management information 232 storesthe logical volume number. The second field stores the redundant groupnumber of the redundant group containing the logical volume specified bythe first field. The third field indicates the striping unit numberindicating the stripe of the redundant group indicated by the secondfield from which the logical volume indicated by the first field isstarted. The fourth field indicates the striping unit number indicatingthe last stripe among the stripes constituting the logical volumeindicated by the first field.

Explanation will be given on the correspondence between theconfiguration information stored in the logical volume information 232and actual logical volume configuration with reference to FIG. 4. FIG. 4shows configuration of the logical volume in the redundant group of theredundant group number 0.

In FIG. 4, reference numerals 600 to 603 respectively indicate the fourshelf-shaped rectangular blocks. Each of the shelf-shaped rectangularblocks represent a hard disk contained in the redundant group of theredundant group number 0. Each shelf of the rectangular blocks representa striping unit of the hard disk. The numerals inside the shelvesrepresent the striping unit numbers. The three dots “ . . .” in a shelfindicate that a plurality of continuous striping units are present.

According to the logical volume information 232 of FIG. 3, the logicalvolume of the logical volume number 260 is composed of stripes ofstriping units numbers 0 to 99. That is, the logical volume of thelogical volume number 260 is composed, in FIG. 4, by using the stripingunits of numbers 0 to 99 in the hard disks 600 to 603.

Similarly, the logical volume of the logical volume number 261 iscomposed of stripes 100 to 199, and the logical volume of logical volumenumber 262 is composed of stripes 200 to 299. The management computer100 can acquire the redundant group management information 231 and thelogical volume management information 232 from the storage apparatus 200via LAN 300.

The storage volume allocation section 240 provides a unit for creating anew logical volume in the redundant group. These units can be controlledfrom the management computer 100 via LAN 300. When creating a logicalvolume by using the storage volume allocation section 240, the redundantgroup number and the logical volume size are specified as parameters.

Here, brief explanation will be given on the storage volume allocationsection 240 although it is not essential for this invention. When thestorage volume allocation section 240 receives the redundant groupnumber and the logical volume size, it firstly checks the redundantgroup management table 231. From this, the hard disk allocated to theredundant group is specified.

Next, the storage volume allocation section 240 checks the logicalvolume management table 232. From this, the specified redundant groupchecks the stripes used. Stripe are allocated for the new volume not tooverlap with these stripes already used. An amount of stripes to beallocated are calculated from the specified size. When the stripes to beallocated to the logical volume are decided as has been described above,the storage volume allocation section 240 adds information on theconfiguration of a new logical volume created as a new line to thelogical volume management information 232.

Hereinafter, explanation will be given on the processing in themanagement computer. The storage allocation section 110 of themanagement computer 100 provides a unit for creating a logical volumeinside the storage apparatus according to the hint which is a parametershowing a characteristic of the storage volume. When a user performsvolume allocation, the user gives at least a desired logical volume sizeand the hint as parameters to the storage allocation section 110. Then,the storage allocation section 110 creates a logical volume inside thestorage apparatus according to the hint.

The hint can specify the following:

Read/write ratio: A value from 0 to 10. The ratio indicates which ofread requests and write requests are greater in the read/write requestsfor the logical volume. When 0 is specified, it is considered that onlyread requests are present. When 10 is specified, it is considered thatonly write requests are present. This ratio may be calledDataDirectdionHint below.

Average I/O size: An average data transfer amount in the reqd/writerequests. In kilo byte unit. This size may be referred to asAccessSizeHint below.

I/O wait time importance: A value from 0 to 10. As this value increases,the I/O wait time becomes important. This may be referred to asAccessLatencyHint.

Data transfer band width importance: A value from 0 to 10. As this valueincreases the data transfer band width becomes important. This may bereferred to as AccessBandwidthWeight below.

Here, as the parameter to the storage allocation section 110, a computercapable of allocating a logical volume may be specified. In this case,the storage allocation section 110 creates a logical volume in thestorage apparatus and sets the storage apparatus and the computer sothat the logical volume can be read/write accessed from the specifiedcomputer.

The management computer 100 provides a user interface (not depicted) foruser to input information for executing storage volume allocation by thestorage allocation section 110. This user interface is provided by thegraphical user interface and command line interface. This embodimentprovides a user interface which can be operated by using a display, akeyboard, and a mouse of the management computer 100 for executing thestorage allocation section 110 by specifying the logical volume size andallocation hint. Moreover, it is possible to provide a user interfacecapable of executing the storage allocation section 110 from a computerother than the management computer 100.

The hint specified by the user when the logical volume is allocated bythe user interface is recorded in the allocation management information150. An example of allocation management information is shown in FIG. 5.As shown in FIG. 5, the allocation management information data format isa table format. Each line of it corresponds to a logical volume. In thisexplanation, a logical volume corresponding to the line will be calledan object logical volume.

The first field of each line stores an identifier for uniquelyidentifying the storage apparatus of the object logical volume. Thisidentifier will be called a storage ID. Here, as the storage ID an IPaddress for controlling the storage apparatus is used. In all the linesof FIG. 5, the first field is filled with “1.0.0.0”. In thisspecification, this represents an IP address in connection of thestorage apparatus 200 to LAN 300. The storage ID in this first field isprovided because it is required in correspondence to the computer systemincluding a plurality of storage apparatuses.

The second field stores an identification number of the object logicalvolume in the storage apparatus specified by the first field. By thefirst field and the second field, the logical volume is uniquelyidentified in the entire information system. The third field stores theredundant group number. The fourth to the seventh field store the hintspecified when the object logical volume is allocated. The fourth field(R/W) stores the read/write ratio. The fifth field (I/O size) stores theI/O size. The sixth field (Trans) stores the I/O wait time importance.The seventh field (Band) stores the bandwidth importance.

FIG. 6 shows a processing flow in the storage allocation section 110.The processing shown in FIG. 6 uses the size of the logical volumeallocated and the hint as the input parameters. These parameters arespecified by the user via the aforementioned user interface.

In steps 1000 to 1030, the RAID level of the redundant group forcreating a logical volume is selected. Firstly, in step 1000, it ischecked whether the AccessDirectionHint (read/write ratio) of thespecified hint is 4 or below. If so, it is considered that the access isoriented to read and the RAID level 5 is selected (step 1030). In step1010, if the hint AccessSizeHint (average I/O size) is 256 kilobytes orabove, the access is considered to be large. The large access means thatthe data transfer amount required in one access is 256 kilobytes orabove. It should be noted that not large access is a small access. Ifthe access is large, the RAID level 5 is selected. Otherwise, the RAIDlevel 1 is selected.

In steps 1040 to 1160, the redundant group for creating a logical volumeis selected. In this step, the RAID level which has been selected in thepreceding step, the values of hints AccessLatencyHint (I/O wait timeimportance) and AccessBandwidthWeight (data transfer bandwidthimportance) are referenced. Step 1040 checks whether theAccessLatencyHint or AccessBandwidthWeight is 0 or above. If thesevalues are 8 or above, it is considered that high access performance isrequired and control is passed to step 1050. Otherwise, control ispassed to the condition judgment of step 1070.

In step 1050, a redundant group satisfying the following conditions isdetected according to the allocation management information 150 and thestorage volume management information 230 acquired from the storageapparatus 200.

-   Condition 1: RAID level selected in step 1020 or 1030.-   Condition 2: Can create a logical volume of specified size.-   Condition 3: Two or one logical volume is included in the redundant    group.-   Condition 4: For the logical volumes contained in the redundant    group, the hint AccessLatencyHint (I/O wait time importance) related    to the logical volumes is 4 or below and the AccessBandwidthWeight    (data transfer bandwidth importance) is 4 or below.

When such a redundant group is detected, control is passed to step 1160.Otherwise, control is passed to step 1080.

Step 1070 checks whether the AccessLatencyHint (I/O wait timeimportance) or AccessBandwidthWeight (data transfer bandwidthimportance) is 4 or above. If these values are 4 or above, control ispassed to step 1080. Otherwise, control is passed to step 1100.

In step 1080, a redundant group satisfying the following conditions isdetected according to the allocation management information 150 and thestorage volume management information 230 acquired from the storageapparatus 200.

-   Condition 1: RAID level selected in step 1020 or 1030.-   Condition 2: Can create a logical volume of specified size.-   Condition 3: Ten or less logical volumes are included in the    redundant group.-   Condition 4: For the logical volumes contained in the redundant    group, the hint AccessLatencyHint (I/O wait time importance) or the    AccessBandwidthWeight (data transfer bandwidth importance) is 3 or    below.

When such a redundant group is detected, control is passed to step 1160.Otherwise, control is passed to step 1100. In step 1100, a redundantgroup satisfying the following conditions is detected according to theallocation management information 150 and the storage volume managementinformation 230 acquired from the storage apparatus 200.

-   Condition 1: RAID level selected in step 1020 or 1030.-   Condition 2: Can create a logical volume of specified size.-   Condition 3: There exists no logical volumes contained in the    redundant group having the hint of AccessLatencyHint (I/O wait time    importance) or the AccessBandwidthWeight (data transfer bandwidth    importance) which is 7 or above.

When such a redundant group is detected, control is passed to step 1160.Otherwise, control is passed to step 1120. In step 1120, a redundantgroup satisfying the following conditions is detected according to theallocation management information 150 and the storage volume managementinformation 230 acquired from the storage apparatus 200.

Condition 1: Can create a logical volume of specified size.

Condition 2: There exists no logical volumes contained in the redundantgroup having the hint of AccessLatencyHint (I/O wait time importance) orthe AccessBandwidthWeight (data transfer bandwidth importance) which is7 or above.

When such a redundant group is detected, control is passed to step 1160.Otherwise, control is passed to step 1140. In step 1140, redundantgroups which can create a logical volume of the specified size areselected at random. If no such redundant group exists, an error iscaused. In step 1160, the redundant group detected is selected as aredundant group for allocating the logical volume.

In step 1170, the selected redundant group and the logical volume sizeare specified for the storage apparatus 200 and creation of the logicalvolume is instructed. Thus, a new logical volume is created by theaforementioned storage volume allocation section 240. In step 1180, theconfiguration information on the logical volume created in step 1170 isadded to the allocation management information 150. Here, theinformation recorded are storage ID, the logical volume number, theredundant group number, and the hint.

It should be noted that the algorithm of the logical volume allocationprocessing explained up to step 1170 is only an example. The presentinvention can be realized by using an algorithm other than thisalgorithm.

The method for logical volume allocation based on the hint has beenexplained.

In this embodiment, monitoring of the logical volume is performed byusing the hint used in volume allocation. The monitoring of the logicalvolume is performed basically by comparing the various performancevalues of the logical volume to threshold values. The threshold valuesare stored in the threshold value information 170.

FIG. 7 explains the contents of the threshold value information 170. Asshown in FIG. 7, the data format of the threshold value information 170is a table format. Each line of the threshold value information 170corresponds to the logical volume of the threshold value managementobject. Each line consists of five fields.

Hereinafter, a logical volume corresponding to each volume will bereferred to as a corresponding logical volume. The first field storesthe storage ID of the corresponding logical volume. The second fieldstores the logical volume number of the corresponding logical volume.The third field stores a threshold value of the average wait time forthe corresponding logical volume. The fourth field stores a thresholdvalue of the average data transfer amount for the corresponding logicalvolume. The fifth field stores a threshold value of the average datatransfer amount per wait time for the corresponding logical volume. Thisvalue is a threshold value of the value decided by the followingequation:(average data transfer amount per second)/{(average processing waittime)*(average number of requests per second)}

In the threshold value information 170, the value 0 means that no valueis decided. That is, the item whose value is 0 is not monitored. Settingof the threshold value is performed by the threshold composing section120. In this embodiment, the monitoring object is a performance value ofthe logical volume.

The processing in the threshold composing section is executed when thelogical volume is allocated. The parameters input for this processingare the storage ID of the logical volume, the logical volume number, andthe hint. The threshold composing section 120 decides a threshold valueaccording to the information indicating the relationship between thehint and the threshold value. In this embodiment, for example, thethreshold composing section 120 decides a threshold value according totwo tables shown in FIG. 8.

Table 801 shows correspondence between the value of theAccessLatencyHint (I/O wait time importance) of the hint and the logicalvolume average access wait time threshold value. The first field of eachline shows the value of the AccessLatencyHint. The second field shows athreshold value of the average access wait time of the logical volumecorresponding to the AccessLatencyHint value shown in the first field.Table 802 shows correspondence between the value of theAccessBandwidthWeight (data transfer bandwidth importance) and thethreshold value of the average data transfer amount per the logicalvolume wait time. The first field of each line shows the value of theAccessBandwidthWeight. The second field shows a threshold value of theaverage data transfer amount per logical volume wait time. It should benoted that in tables 801 and 802, the threshold value 0 means that thethreshold value is not monitored.

The threshold composing section 120 decides the monitoring thresholdvalue of the logical volume for storing the information on therelationship between the hints and the threshold values according to thetables 801 and 802 in the threshold value information 170. Here, in thisembodiment, the monitoring threshold values are automatically decided bythe management computer 100. However, it is also possible to prompt auser to correct or acknowledge a threshold value by using theaforementioned user interface before deciding the threshold value.

The performance information 160 stores a performance value acquired fromthe storage apparatus 200. FIG. 9 explains information stored in theperformance information 160. Especially performance information 161 ofthe logical volume 260 is detailed. As shown in FIG. 9, the performanceinformation of the logical volume 260 is in a table format having 9fields. Each line corresponds to a time when the performance informationconcerning the logical volume 260 is acquired. The first field storesthe time when the performance information is acquired. The second fieldstores the average I/O size of read access. The third field stores theaverage data transfer amount per read access unit time. Here, the unittime is second. The fourth field stores the average processing wait timeof read access. The fifth field stores the average number of readaccesses per unit time. Here, the unit time is second. The sixth fieldstores the average I/O size of write access. The seventh field storesthe average data transfer amount of write access per unit time. Here,the unit time is second. The eighth field stores write access averageprocessing wait time. The ninth field stores the number of average writeaccesses per unit time. Here, the unit time is second.

The performance information of the logical volumes 261 to 264 are alsostored in the performance information 160 like the logical volume 260.The data format of the performance information of the logical volumes261 to 264 is identical to the data format of the performanceinformation 161 of the logical volume 260.

The performance information acquisition section 130 periodicallyacquires the performance information of the logical volumes 260 to 264from the storage apparatus 200 and adds it to the performanceinformation 160. Moreover, at the timing when the performanceinformation is acquired from the storage apparatus 200, the performanceinformation acquired is compared to the threshold value set in thethreshold value information 170. The processing flow in the performanceinformation acquisition section 130 is shown in the flowchart of FIG.10. Explanation will be given on the performance acquisition section 130with reference to FIG. 10.

Steps 1410 to 1440 constitute a loop structure. This loop processing isexecuted for the logical volume to be monitored. Step 1410 selects alogical volume for which performance information is to be acquired.Here, the logical volume specified by the first field and the secondfield of each line of the threshold value information 170 issuccessively selected from the first line of the threshold valueinformation 170 (from the uppermost line in the figure).

In step 1420, the performance information on the logical volume selectedin step 1410 is acquired. The performance information acquired here arevalues corresponding to the respective fields of the logical volumeperformance information. That is, the average I/O size of read access,the average data transfer amount per unit time of the read access, theaverage processing wait time of read access, the average number of readaccesses per unit time, the average I/O size of write access, theaverage data transfer amount per unit time of write access, the averageprocessing wait time of write access, and the average number of writeaccesses per unit time.

In order to acquire these values, the performance informationacquisition section 130 request the storage apparatus indicated by thefirst field of the threshold value information 170 t output performanceinformation. In the storage apparatus 200, the performance informationacquisition request executed in step 1420 of the performance informationacquisition section 130 is processed by the performance valuenotification section 250.

In step 1430, the performance information acquired in step 1420 is addedto the performance information 160. Here, the time when the performanceinformation is acquired is stored as the first field. In step 1440, ifthe performance information acquisition processing of all the logicalvolumes contained in the threshold value information 170 is notcomplete, the processing from step 1410 is performed to the next logicalvolume.

Next, explanation will be given on the monitoring using a hints and athreshold value. As has been described in the background art, themanagement system of the computer system notifies a warning to a userwhen the various monitoring numeric value items of the device to bemonitored violates a predetermined threshold value. In this invention,when the warning is notified to the user, a message concerning the hintis also notified. This operation is realized by the warning notificationsection 140.

FIG. 11 is a flowchart showing a processing flow in the warningnotification section 140. The processing shown in FIG. 11 is executedafter the performance information collection processing of the logicalvolume is executed in the performance information acquisition section130. The processing shown in FIG. 11 is for a single logical volume. Theprocessing shown in FIG. 11 is executed for all the logical volumesspecified by the first and the second field of the threshold valueinformation 170. The input parameters of the processing shown in FIG. 11are a logical volume number and a storage ID of the apparatus providingthe logical volume. In the explanation below, the logical volumespecified by the input parameter will be referred to as an objectlogical volume. In the processing shown in FIG. 11, the performanceinformation used for inspection is the latest acquired by theperformance information acquisition section 130.

In step 1600, it is checked whether the average data transfer amount perprocessing wait time of the read and write request is below a thresholdvalue. The threshold value used is the average data transfer amountthreshold value per processing wait time of the object logical volume.Here, the value of the inspection object used is based on the latestperformance information on the object logical volume stored in theperformance information 160. For each of read and write, the averagedata transfer amount is divided by the average processing wait time toobtain a quotient, which is used. That is, two values of read and writeare used as values of inspection objects.

The two values of inspection objects are compared to the aforementionedthreshold value. If one of them is lower than the threshold value, it isassumed that a performance problem has occurred and control is passed tostep 1620. Otherwise, control is passed to step 1610. In step 1610, itis checked whether the average processing wait time of read and writerequest for the object logical volume is above a threshold value. Thethreshold value used here is an average processing wait time thresholdvalue stored in the threshold value information 170 and corresponding tothe object logical volume.

The value of the inspection object used here is the latest performanceinformation on the object logical volume stored in the performanceinformation 160, i.e., the average processing time for each of read andwrite. That is, two values of read and write are used as values ofinspection objects. The two values of inspection objects are compared tothe aforementioned threshold value. If one of them exceeds the thresholdvalue, it is assumed that a performance problem has occurred and controlis passed to step 1620. Otherwise, control is passed to step 1770.

Step 1620 checks whether the characteristics of actual access to theobject logical volume (read/write ratio and I/O size) are appropriatefor the RAID level of the redundant group to which the object logicalvolume belongs. Hereinafter, the RAID level of the redundant group ofthe object logical volume will be referred to simply as the RAID levelof the object logical volume.

When the RAID level of the object logical volume is 1, thecharacteristic of the access to the object logical volume is assumed tobe appropriate for the RAID level if both of the following conditionsare satisfied:

-   Condition 1: Average write I/O size is 256 kilobytes or below.-   Condition 2: Average read IOPS is smaller than the average write    multiplied by 1.5.

When the RAID level of the object logical volume is 5, thecharacteristic of the access to the object logical volume is assumed tobe appropriate for the RAID level if one of the conditions 1 or 2 orboth of them are not satisfied. If the characteristic of the access tothe object logical volume is judged to be appropriate for the RAIDlevel, control is passed to step 1680. Otherwise, control is passed tostep 1640. It should be noted that the aforementioned conditions 1 and 2are equivalent to the conditions for selecting the RAID level in thelogical volume allocation.

In step 1640, conformity between the allocation hint and the actualaccess characteristic of the object logical volume is checked. In thisstep, if one of the following conditions is satisfied, it is judged thatthe actual access characteristic is not appropriate for the allocationhint of the object logical volume.

Condition 1: The average write I/O size as the latest performanceinformation on the object logical volume stored in the performanceinformation 160 is 256 kilobytes or below and the I/O size of theallocation hint is 250 kilobytes or above.

Condition 2: The average write I/O size as the latest performanceinformation on the object logical volume stored in the performanceinformation 160 is 256 kilobytes or above and the I/O size of theallocation hint is 250 kilobytes or below.

Condition 3: The read IOPS as the latest performance information on theobject logical volume stored in the performance information 160 is thewrite IOPS multiplied by 1.5 or below and the read/write ratio of theallocation hint is 6 or below.

Condition 4: The read IOPS as the latest performance information on theobject logical volume stored in the performance information 160 is thewrite IOPS multiplied by 1.5 or above and the read/write ratio of theallocation hint is 6 or above.

In step 1650, a warning message is created to indicate the inconformitybetween the actual access characteristic for the object logical volumeand the allocation hint of the object logical volume judged in step1640. For Conditions 1 to 4, a messages created when the respectiveconditions are satisfies are as follows. It should be noted that theinconformity of the RAID level is generated.

1. When Condition 1 or 2 is satisfied, the message says that “the I/Osize of access to the <<object logical volume>> does not coincide withthe I/O size specified for the hint.”

2. When Condition 3 or 4 is satisfied, the message says that “theread/write ratio to/from the <<object logical volume>> does not coincidewith the read/write ratio specified for the hint.”

3. When none of Conditions 1 to 4 is satisfied, the message says that“<<the object logical volume>> allocated is not a logical volumeappropriate for the hint.” The part <<object logical volume>> isreplaced by a word representing the object logical volume.

After the message is created in step 1650, control is passed to step1670. Steps 1670 to 1750 check the redundant group containing the objectlogical volume, i.e., the hint and actual access frequency of thelogical volume other than the object logical volume contained in theredundant group.

Such a check is performed because of the following reasons. In thisembodiment, the logical volume given a low value for theAccessLatencyHint (I/O wait time importance) and theAccessBandwidthWeight (data transfer bandwidth importance) in the hintduring the allocation is assumed to have a low access frequency.Accordingly, for the redundant group containing such logical volumes, alogical volume having a high AccessLatencyHint and AccessBandwidthWeightmay be allocated later.

Under such a condition, if the access to the logical volume whose accesshas been considered low increases, the logical volume requiring a highaccess frequency allocated later may be affected and its performance maybe lowered. Although such performance lowering (threshold valueviolation) may be recognized, its cause may not be known.

Accordingly, for the threshold value violation by the object logicalvolume, notification of a logical volume which may possibly a cause to auser will help the user to study the performance improvement of thelogical volume.

In step 1670, for the redundant group to which the object logical volumebelongs, one logical volume (other than the object logical volume)belonging to the redundant group is selected. Selection of the logicalvolume can be performed by checking the logical volume managementinformation 232. It should be noted that steps 1670 to 1750 constitute aloop structure but in step 1670, it is assumed that a logical volumewhich has been selected once will not be selected again. Hereinafter,the logical volume selected in step 1670 will be referred to as theselected logical volume.

Step 1680 makes a check for the selected logical volume, i.e.,conformity between the AccessLatencyHint (I/O wait time importance) andAccessBandwidthWeight (data transfer bandwidth importance) which arehints during allocation and the performance value. Here, it is checkedwhether access to the selected logical volume is increased in spite ofthe low value of the AccessLatencyHint and AccessBandwidthWeight of theselected logical volume. If the selected logical volume is in such astate, control is passed from step 1690 to step 1700. Otherwise, controlis passed to step 1750. As will be detailed later, the processing ofstep 1700 creates a message describing affect to the performance.

Firstly, AccessLatencyHint and AccessBandwidthWeight of the selectedlogical volume are acquired from the allocation management information150. Next, the read IOPS and write IOPS are acquired from theperformance information by the latest performance information of theselected logical volume. If the AccessLatencyHint andAccessBandwidthWeight is lass than 4 and the sum of the read IOPS andthe write IOPS is greater than a predetermined value, the selectedlogical volume is assumed to be a logical volume affecting theperformance of the object logical volume.

Step 1700 creates a message describing that the selected logical volumehas an affect to the performance of the object logical volume. Themessage created here is as follows. “<<The selected logical volume>> isaccessed with a high frequency unlike the specified hint”. <<Theselected logical volume>> is replaced by a word representing a selectedlogical volume.

Step 1750 is the end of the loop. This step checks whether all thelogical volumes contained in the redundant group of the object logicalvolume have been subjected to the processing of steps 1670 to 1700. Ifthere is a logical volume not processed, control is returned to step1670. Here, the logical volumes belonging to the same redundant groupinteract their performances as has been described above. Such aphenomenon can also be seen depending on the RAID level.

A write access of a small I/O size (equal to the striping unit or below)to the redundant group of RAID level 5 gives a great affect to theperformance of the entire redundant group. Accordingly, in the loop ofsteps 1670 to 1700, with respect to the selected logical volume, it iseffective to check conformity between the RAID level and the performancevalue by the method described in steps 1620 to 1640 and create a messageas has been described in step 1650.

The processing of step 1760 is executed when no threshold valueviolation is recognized in steps 1600 and 1610. Here, the target is tonotify a user that the access frequency is actually low although a highperformance is required of the object logical volume by the hint. Step1760 checks whether the average data transfer amount of the objectlogical volume is lower than the threshold value.

The threshold value in this step is the data transfer amount thresholdvalue of the object logical volume stored in the threshold valueinformation 170. This step compares the sum of the average read datatransfer amount and the average write data transfer amount of the objectlogical volume stored in the performance information 160 with theaforementioned threshold value. As a result, if the sum is lower thanthe threshold value, the object logical volume is assumed to be alogical volume which has an excessively high performance for the actualaccess. And in step 1770, a message is created. Otherwise, this seriesof processing is terminated.

Step 1770 creates a message as follows. “<<The object logical volume>>has an excessively high performance for the actual use.” The part <<theobject logical volume>> is replaced by a character string representingthe object logical volume.

Step 1780 notifies a warning of threshold value violation to the user.When notifying the warning, the messages created in steps 1650, 1700,and 1770 are included. The warning is notified to the user via theaforementioned user interface. It is also possible to notify the user byusing the log recording function such as syslog. Moreover, it ispossible to use the message exchange function such as e-mail. Moreover,it is also possible to notify the warning to the user by using theprotocol, for management such as SNMP.

Thus, the logical volume is monitored and if a threshold value violationis generated, an appropriate message is reported to the user.

[Second Embodiment]

Description will now be directed to a second embodiment of the presentinvention. FIG. 12 shows the second embodiment of the present invention.The sections and information equivalent to the storage allocationsection 110, the threshold composing section 120, the warningnotification section 140, the allocation management section 150, theperformance information 160, and the threshold information which arecontained in the management computer 100 (see FIG. 2) in the firstembodiment are contained in the apparatus in the second embodiment. Thestorage apparatus 2200 is an extended device of the storage apparatus200 (see FIG. 2) for containing these sections and information.

The storage apparatus 220 includes a storage allocation section 2110, amonitoring section 2120, a warning notification section 2140, allocationmanagement information 2150, performance information 2160, and thresholdinformation 2170. These sections and information are equivalent to thesections and information of the same names in the management computer100 of the first embodiment which are operated in the storage apparatus2200. In the second embodiment, the controller 210 includes a CPU 201and a memory 202 and has an ability to interpret and execute a program.The sections 220, 240, 250, 2250, 2110, 2120, and 2140 are programswhich are stored in the memory 202 and executed by the controller 210.It should be noted that the present invention can also be realized byusing the storage apparatus having dedicated hardware for the functionsequivalent to the sections 220, 240, 2250, 2110, 2120, and 2140.

In the second embodiment, the functions of the performance informationacquisition section 130 and the performance value notification section250 are realized by the performance value notification section 2250.That is, the performance value notification section 2250 accumulatesinformation on the performance of the logical volumes 260 to 264 in theperformance information 2160.

The management computer 2100 is an ordinary computer having a userinterface 180. By using the user interface 2180, like the firstembodiment, the user can control the storage allocation section 2110,the monitoring section 2120, and the warning notification section 2140of the storage apparatus 2200. Moreover, the management computer 100 canalso have the effect of the present invention in the second embodimentfrom the explanation of the first embodiment concerning the allocationmanagement information 150, the performance information 160, and thethreshold value information 170.

Thus, the two embodiments have been explained. Here, additionalexplanation will be given on the embodiments.

In the first and the second embodiment, the storage apparatus containedin the computer system is the storage apparatus 200 or 2200. However,the present invention can also be applied to a computer systemcontaining a plurality of storage apparatuses. In the first and thesecond embodiment, only one FC switch is contained in the computersystem. However, the essential quality of the present invention will notbe changed by the number of the FC switches.

The first and the second embodiment can be extended in such a mannerthat the performance information can be acquired not only from thestorage apparatus but also from the computer or the FC switch andthreshold values can be set for them.

There is a storage apparatus which has a function to improve theperformance inside the storage apparatus. For example, theaforementioned storage area network has a function for always containingthe data stored in the logical volume in the cache memory (cacheresident function). This dramatically improves the access performance tothe logical volume. In the processing flow explained with reference toFIG. 11, a message is created in steps 1650 and 1700. In these steps, itis possible to create a message to suggest application of theaforementioned cache resident function for the logical volume.

Moreover, it is possible to calculate the size of the appropriate cachememory size for the logical volume and automatically apply the cacheresident function. In this case, the message includes that the cacheresident function is automatically applied.

Moreover, in addition to the cache resident function, the performanceimprovement function includes a logical volume movement function formoving data stored in a logical volume to another logical volume and aband control function for controlling the bandwidth used by the I/Orequest from a particular computer in the FC interface.

The present invention has been explained through the embodiments.However, the present invention is not to be limited to these embodimentsbut can be modified in various ways without departing from the spirit ofthe invention.

1. A management computer for managing a computer system which includes adata processor and a storage apparatus coupled to the data processor viaa first network, the data processor and the storage apparatus beingcoupled to the management computer via a second network, the computersystem further including a plurality of logical volumes allocated fromthe storage apparatus, each logical volume belonging to one of aplurality of redundant groups, the management computer comprising: astorage allocation unit that allocates said logical volumes; aperformance information acquisition unit that periodically acquires,from said storage apparatus, latest performance values of each of thelogical volumes, said latest performance values indicating states ofsaid logical volumes; a threshold composing unit that determines athreshold performance value corresponding to each logical volume andmaintains a threshold information comprising threshold performancevalues of said logical volumes; and a warning unit that selects alogical volume, conducts a comparison of a latest performance value ofsaid selected logical volume with its corresponding thresholdperformance value, and notifies a user with a warning message when itslatest performance value deviates from its corresponding thresholdperformance value, wherein said storage allocation unit is operable toreceive from said user a request to create a new logical volume, saidrequest including a plurality of hint values specified according to saidCommon Information Model (CIM) as parameters indicating a feature ofsaid new logical volume, said hint values being stored on a per logicalvolume basis as allocation management information, said storageallocation unit is further operable to conduct, based on said allocationmanagement information, a first-step search that searches alreadycreated redundancy groups to detect a redundant group including alreadycreated logical volumes having first predetermined hint values lowerthan said requested hint values of said new logical volume, if saidfirst-step search was successful in detecting a redundancy group, saidstorage allocation unit determines said redundancy group thus detectedas a redundancy group to which said new logical volume is to belong,otherwise, said storage allocation unit conducts, based on saidallocation management information, a second-step search that searchessaid already created redundancy groups to detect a redundant groupincluding already created logical volumes having second predeterminedhint values higher than said first predetermined hint values, and ifsaid second-step search was successful in detecting a redundancy group,said storage allocation unit determines said redundancy group thusdetected in said second-step search as a redundancy group to which saidnew logical volume is to belong; otherwise, said storage allocation unitselects an arbitrary redundant group to which said new logical volume isto belong.
 2. The management computer according to claim 1, wherein saidrequested hint values include AccessLatencyHint and AccessBandwidthWeight specified in the CIM standard.
 3. The management computeraccording to claim 2, wherein said latest performance values of each ofsaid logical volumes are expressed as hint values obtained by usingAccessLatencyHint and AccessBandwidthWeight values, based on a tablecomprising a correspondence relationship between said performance valuesand said hint values, said warning unit selects an already createdlogical volume of a redundancy group to which said new logical volumebelongs, said warning unit conducts another comparison that compares alatest performance values expressed by using AccessLatencyHint andAccessBandwidthWeight values of said already created logical volume withits corresponding requested hint values, based on said table and saidallocation management information, and if said another comparisonindicates that said latest performance values of said selected logicalvolume are higher than said corresponding requested hint values thereof,said warning unit notifies said user of a warning message indicatingthat said selected logical volume may exert a bad influence on a logicalvolume of said redundancy group to which said selected logical volumebelongs.
 4. The management computer according to claim 1, wherein saidfirst network is a storage area network (SAN) and another data processoris further provided, with said data processor and said another dataprocessor being coupled to said storage apparatus via a Fibre Channel(FC) switch.
 5. The management computer according to claim 1, whereinsaid second network is a local area network (LAN).
 6. A managementcomputer for managing a computer system which includes a data processorand a storage apparatus coupled to said data processor via a firstnetwork, said data processor and said storage apparatus being coupled tosaid management computer via a second network, said computer systemfurther including a plurality of logical volumes each thereof belongingto one of a plurality of redundant groups and being allocated in saidstorage apparatus, the management computer comprising: a storageallocation unit that allocates logical volumes of data to be accessibleby said data processor; a performance information acquisition unit thatperiodically acquires, from said storage apparatus, latest performancevalues of each of said logical volumes, said latest performance valuesindicating a state of each of said logical volumes; a thresholdcomposing unit that determines threshold values of said performancevalues of each of said logical volumes, a correspondence relationshipbetween said performance values and said threshold values being storedon a logical volume basis as threshold information; and a warning unitthat selects a logical volume, conducts a comparison of a latestperformance value of said logical volume thus selected with acorresponding threshold value based on said threshold information, andnotifies a user with a warning message indicating that said logicalvolume thus selected is inappropriate with regard to said correspondingthreshold value, if said comparison indicates that said latestperformance value of said logical volume thus selected deviates fromsaid corresponding threshold value, wherein said storage allocation unitreceives from said user a request to create a new logical volume, saidrequest including hint values obtained by using input/output (I/O) waittime and data transfer bandwidth values as performance values of saidnew logical volume, said requested hint values thus received beingstored on a per logical volume basis as allocation managementinformation, said storage allocation unit determines, based on saidallocation management information, a redundancy group to which said newlogical volume is to belong, said threshold composing unit expressessaid latest performance values of each of said logical volumes by hintvalues obtained by using I/O wait time and data transfer bandwidthvalues, based on a table storing a correspondence relationship betweensaid performance values and said hint values, said warning unit selectsone already created logical volume of said redundancy group to whichsaid new logical volume belongs, said warning unit conducts anothercomparison that compares said latest performance values expressed bysaid hint values of said logical volume thus selected with saidcorresponding requested hint values of said logical volume thusselected, based on said table and said allocation managementinformation, and if said another comparison indicates that said latestperformance values of said selected logical volume are higher than saidcorresponding requested hint values thereof, said warning unit notifiessaid user of a warning message indicating that said selected logicalvolume may exert a bad influence on a logical volume of said redundancygroup to which said new logical volume belongs.
 7. A method for managinga computer system which includes a data processor and a storageapparatus coupled to said data processor via a first network, with saiddata processor and said storage apparatus being coupled to a managementcomputer via a second network, and a plurality of logical volumes eachthereof belonging to one of a plurality of redundant groups and beingallocated in said storage apparatus, the method comprising: allocating,by a storage allocation unit, logical volumes of data to be accessibleby said data processor; periodically acquiring, by a performanceinformation acquisition unit, latest performance values, from saidstorage apparatus, of each of said logical volumes, said latestperformance values indicating a state of each of said logical volumes;and determining, by a threshold composing unit, threshold values of saidperformance values of each of said logical volumes, a correspondencerelationship between said performance values and said threshold valuesbeing stored on a logical volume basis as threshold information; in awarning unit, selecting a logical volume, conducting a comparison of alatest performance value of said logical volume thus selected with acorresponding threshold value based on said threshold information, andnotifying a user with a warning message indicating that said logicalvolume thus selected is inappropriate with regard to said correspondingthreshold value, if said comparison indicates that said latestperformance value of said logical volume thus selected deviates fromsaid corresponding threshold value; receiving from said user, by saidstorage allocation unit, a request to create a new logical volume, saidrequest including a plurality of hint values specified by the CommonInformation Model (CIM) defined by the Distributed Management Task Force(DMTF) as parameters indicating a feature of said new logical volume,said requested hint values received from said user being stored on alogical volume basis as allocation management information; conducting,by said storage allocation unit based on said allocation managementinformation, a first-step search that searches already createdredundancy groups to detect a redundant group including already createdlogical volumes having first predetermined hint values lower than saidrequested hint values of said new logical volume; if said first-stepsearch was successful in detecting a redundancy group, determining, bysaid storage allocation unit, said redundancy group thus detected as aredundancy group to which said new logical volume is to belong;otherwise, conducting, by said storage allocation unit based on saidallocation management information, a second-step search that searchessaid already created redundancy groups to detect a redundant groupincluding already created logical volumes having second predeterminedhint values higher than said first predetermined hint values; and ifsaid second-step search was successful in detecting a redundancy group,determining, by said storage allocation unit, said redundancy group thusdetected in said second-step search as a redundancy group to which saidnew logical volume is to belong; otherwise, selecting, by said storageallocation unit, an arbitrary redundant group to which said new logicalvolume is to belong.
 8. The method according to claim 7, wherein saidrequested hint values include AccessLatencyHint and AccessBandwidthWeight specified by CIM.
 9. The method according to claim 8, whereinsaid threshold composing unit expresses said latest performance valuesof each of said logical volumes by hint values obtained by usingAccessLatencyHint and AccessBandwidth Weight values, based on a tablestoring a correspondence relationship between said performance valuesand said hint values, said method further comprising steps of:selecting, by said warning unit, one already created logical volume ofsaid redundancy group to which said new logical volume belongs,conducting, by said warning unit, another comparison that compares saidlatest performance values expressed by using AccessLatencyHint andAccessBandwidth Weight values of said logical volume thus selected withsaid corresponding requested hint values of said logical volume thusselected, based on said table and said allocation managementinformation, and if said another comparison indicates that said latestperformance values of said selected logical volume are higher than saidcorresponding requested hint values thereof, notifying, by said warningunit notifies, said user of a warning message indicating that saidselected logical volume may exert a bad influence on a logical volume ofsaid redundancy group to which said new logical volume belongs.
 10. Themethod according to claim 7, wherein said first network is a storagearea network (SAN) and another data processor is further provided, withsaid data processor and said another data processor being coupled tosaid storage apparatus via a Fibre Channel (FC) switch.
 11. The methodaccording to claim 7, wherein said second network is a local areanetwork (LAN).
 12. A method for managing a computer system whichincludes a data processor and a storage apparatus coupled to said dataprocessor via a first network, with said data processor and said storageapparatus being coupled to a management computer via a second network,and a plurality of logical volumes each thereof belonging to one of aplurality of redundant groups and being allocated in said storageapparatus, the method comprising: allocating, by a storage allocationunit, logical volumes of data to be accessible by said data processor;periodically acquiring, by a performance information acquisition unit,latest performance values, from said storage apparatus, of each of saidlogical volumes, said latest performance values indicating a state ofeach of said logical volumes; and determining, by a threshold composingunit, threshold values of said performance values of each of saidlogical volumes, a correspondence relationship between said performancevalues and said threshold values being stored on a logical volume basisas threshold information; in a warning unit, selecting a logical volume,conducting a comparison of a latest performance value of said logicalvolume thus selected with a corresponding threshold value based on saidthreshold information, and notifying a user of with a warning messageindicating that said logical volume thus selected is inappropriate withregard to said corresponding threshold value, if said comparisonindicates that said latest performance value of said logical volume thusselected deviates from said corresponding threshold value; receiving, bysaid storage allocation unit, from said user a request to create a newlogical volume, said request including hint values obtained by using I/Owait time and data transfer bandwidth values as performance values ofsaid new logical volume, said requested hint values thus received beingstored on a logical volume basis as allocation management information;determining, by said storage allocation unit, based on said allocationmanagement information, a redundancy group to which said new logicalvolume is to belong; expressing, by said threshold composing unit, saidlatest performance values of each of said logical volumes by hint valuesobtained by using I/O wait time and data transfer bandwidth values,based on a table storing a correspondence relationship between saidperformance values and said hint values; selecting, by said warningunit, one already created logical volume of said redundancy group towhich said new logical volume belongs; conducting, by said warning unit,another comparison that compares said latest performance valuesexpressed by said hint values of said logical volume thus selected withsaid corresponding requested hint values of said logical volume thusselected, based on said table and said allocation managementinformation, and if said another comparison indicates that said latestperformance values of said selected logical volume are higher than saidcorresponding requested hint values thereof, notifying, by said warningunit, said user of a warning message indicating that said selectedlogical volume may exert a bad influence on a logical volume of saidredundancy group to which said new logical volume belongs.
 13. Acomputer readable storage medium having a computer program for acomputer system which includes a data processor and a storage apparatuscoupled to said data processor via a first network, with said dataprocessor and said storage apparatus being coupled to a managementcomputer via a second network, and a plurality of logical volumes eachthereof belonging to one of a plurality of redundant groups and beingallocated in said storage apparatus, wherein said management computercomprises: a storage allocation unit that allocates logical volumes ofdata to be accessible by said data processor; a performance informationacquisition unit that periodically acquires, from said storageapparatus, latest performance values of each of said logical volumes,said latest performance values indicating a state of each of saidlogical volumes; and a threshold composing unit that determinesthreshold values of said performance values of each of said logicalvolumes, a correspondence relationship between said performance valuesand said threshold values being stored on a logical volume basis asthreshold information; and a warning unit that selects a logical volume,conducts a comparison of a latest performance value of said logicalvolume thus selected with a corresponding threshold value based on saidthreshold information, and notifies a user with a warning messageindicating that said logical volume thus selected is inappropriate withregard to said corresponding threshold value, if said comparisonindicates that said latest performance value of said logical volume thusselected deviates from said corresponding threshold value, the computerprogram comprising: codes for said storage allocation unit to receive,from said user, a request to create a new logical volume, said requestincluding a plurality of hint values specified by Common InformationModel (CIM) defined by Distributed Management Task Force (DMTF) asparameters indicating a feature of said new logical volume, saidrequested hint values received from said user being stored on a logicalvolume basis as allocation management information; codes for saidstorage allocation unit to conduct, based on said allocation managementinformation, a first-step search that searches already createdredundancy groups to detect a redundant group including already createdlogical volumes having first predetermined hint values lower than saidrequested hint values of said new logical volume; codes for said storageallocation unit, if said first-step search was successful in detecting aredundancy group, to determine said redundancy group thus detected as aredundancy group to which said new logical volume is to belong;otherwise, to conduct, based on said allocation management information,a second-step search that searches said already created redundancygroups to detect a redundant group including already created logicalvolumes having second predetermined hint values higher than said firstpredetermined hint values; and codes for said storage allocation unit,if said second-step search was successful in detecting a redundancygroup, to determine said redundancy group thus detected in saidsecond-step search as a redundancy group to which said new logicalvolume is to belong; otherwise, to select an arbitrary redundant groupto which said new logical volume is to belong.